Alloy



Patented Jan. 20, 1942 OFFICE ALLOY Jacob Trantin, In, Youngstown, Ohio No Drawing.

Application October 26, 1940,

Serial No. 363,001

1 Claim.

This invention relates to steel alloys capable of being cast, and more particularly, is concerned with alloys having high wear resistance and freedom from scale pickup and specifically adapted to use as guides in a hot bar rolling-mill.

This application is a continuation in part of my copending application S. N. 326,429, filed March 28, 1940, and entitled Alloy.

Heretofore, in rolling bars while hot, guides of white or gray cast iron have been employed to position the bars and to direct them properly into the rolls. However, such cast iron guides have a relatively shortlife and are quite subject to scratching, wear and deposition of hot scale on them. Scratched or marred guides, as by scale or otherwise, often objectionably mar the work. Attempts have been made to heat treat or harden the cast iron guides, as by casting them against a chill, all without solving the existing problem. Further, efiorts have been made to employ other materials as guides. However, because of brittleness, lack of wear resistance, or susceptibility to scale deposition, none of the experiments with other materials have proven successful and the cast iron guide with all its faults is still employed.

It is the-general object of my invention to provide an improved guide for directing and controlling metal bars' in the hot rolling thereof.

Another object of my invention is the provision of an improved steel alloy capable of being cast and characterized by wear resistance and lack of susceptibility of metal deposit thereon. I

Another object of my invention resides in providing a castable steel alloy particularly subject to controlled heat treatment whereby acast article can be given a desired hardness greater than its hardness in an annealed state.

The foregoing and other objects of my invention are achieved by the provision of a bar mill guide of cast steel having about 5 to about 30 percent chromium therein, about .75 to about 2.00 percent carbon, and over 5 to about percent copper therein. More completely, I provide a castable steel alloy of the indicated composition including, furthenbetween about .40 to about 1 percent manganese, about .40 to about 3 percent silicon, up to about 3.5 percent molybdenum, to about 1 percent vanadium, up to about 5 percent aluminum, up to about 3.5 percent cobalt, up to' about 5 percent nickel, and up to about 3.5 percenttungsten.

Although myimproved alloy is useful in many relations and wherever wear resistance and lack of susceptibility to metal or other deposit are important, nevertheless,my invention is particularly adapted to and concerned with the provision of improved means for forming or guiding hot metal during rolling or forming, and

specifically is concerned with providing guides for mills for rolling hot bars.

According to my invention, I provide a steel alloy having an analysis including between about .75 and about 2 percent carbon, about .40 to about 1 percent manganese, about .40 to about 3 percent silicon, about 5 to about 30 percent chromium, over 5 to about 15 percent copper, and the remainder substantially iron. Usually, I prefer to have up to about 3.5 percent molybdenum, up to about 5 percent nickel, and up to about 1 percent vanadium in the alloy, also. The molybdenum adds hardness, the nickel adds toughness, and the vanadium acts as a scavenger and gives fluidity. Instead of the molybdenum and nickel, or in combination therewith, I may use up to about 3.5 percentcobalt for hardness and toughness, up to about 5 percent aluminum for hardness and resistance to pickup, and up to about 3.5 percent tungsten for hardness. The nickel, molybdenum, cobalt, aluminum, and tungsten comprise a group, and usually up to about 3.5 percent of a material or a combination of materials selected from this group is included in the alloy. The usual percentages of sulphur and phosphorus present in open hearth or Bessemer commercial steels are not objectionable nor are traces of other alloying agents or impurities. Further, it should be understood that increasing the manganese content of my alloy permits a decrease in the chromium content and vice versa. Variations in the exact composition of my alloy to achieve a desired or a particular result, all as well known to those skilled in the art, may be resorted to without departing from the basic concept ofmy invention.

One guide for bar mills which possessed the desired characteristics of long wear and lack of susceptibility to scale deposition comprised the following composition: carbon 1.15 percent; manganese .45 percent; silicon 1.61 percent; chromium 14.56 percent; molybdenum .40 percent; vanadium .035 percent; copper 7.34 percent and the balance substantially iron.

Preferably I add the copper to the alloy during the end of the melt or to the ladle in order to avoid oxidation. However, the copper may be put in the batch initially in suflicient quantities to allow for oxidation loss.

An important feature of my invention resides in the provision of a castable steel alloy which lends itself to controlled heat treatment. Specifically, I am able to obtain relatively wide degrees of hardness in my improved alloy by controlled heat treatment with standard heat treating methods. Thus, while my alloy has many advantageous and desirable characteristics in an annealed state, its hardness can be increased by appropriate heat treatment to best adapt it for any given use. For example, in making a bar mill guide I raise the temperature of the guide after casting to about 1850 degrees Fahrenheit or more and oil quenched. The resulting Brinell is in excess of 350, but without obtaining an undesirable Charpy value. a

From the foregoing, it will be recognized that the objects of my invention have been achieved and that I have provided a castable steel alloy particularly adapted to act as a guiding or forming member for hot metal and characterized by wear resistance and long life without the deposition thereon of scale. In fact, the bar mill guides of my invention have in commercial operation outlasted the usual cast iron guide many times over and in one given installation over five mil-.

casions the guides were removed, dressed and returned to duty.

Although in accordance with the patent statutes, I have particularly described my invention,

it will be understood that I am not to be limited thereto or thereby, but that the scope of my invention is defined in the appended claim.

I claim:

A ferrous alloy having an analysis including between .75 and 2.00 percent carbon, .40 to 1 percent manganese, .40 to 3.00 percent silicon, 5.00 to 30.00 percent chromium, 5.00 to 15.00 percent copper, and the remainder substantially all iron, said alloy being, capable of being cast, and being characterized by wear resistance and freedom from hot metal scale pickup.

JACOB TRAN'I'IN, J R. 

